public class MyCircularQueue {
    public int[] elem;//存放数据
    public int front;//指向队头
    public int rear;//指向队尾
    
    MyCircularQueue(int k) {
        elem = new int[k];
    }
    
    //入队
    public boolean enQueue(int value) {
        if (isFull()) {
            return false;
        }
        elem[front] = value;
        rear = (rear + 1) % elem.length;
        return true;
    }
    
    //出队
    public boolean deQueue() {
        if (isEmpty()) {
            return false;
        }
        front = (front + 1) % elem.length;
        return true;
    }
    
    //得到队头元素
    public int Front() {
        if (isEmpty()) {
            return -1;
        }
        return elem[front];
    }
    
    //得到队尾元素
    public int Rear() {
        if (isEmpty()) {
            return -1;
        }
        int index = (rear == 0) ? elem.length - 1 : rear - 1;
        return index;
    }
    
    //判空 front和rear相遇
    public boolean isEmpty() {
        return front == rear;
    }
    
    //判空 front和rear相遇
    public boolean isFull() {
        return (rear + 1) % elem.length == front;
    }
}
